Study On Growth And Scintillation Properties Of Cs₂NaGdBr₆:Ce Crystal

Cs₂NaGdBr₆:Ce crystal belongs to the cubic crystal system with high symmetry structure and space group is m3 Fm,which is a newly discovered type of elpasolite scintillation crystals.Not only there were few direct reports on the crystal internationally,but also none of any reports about the crystal has ever been seen in the domestic at present.According to these reports,we knew that Cs₂NaGdBr₆:Ce crystal has excellent scintillation performance: relatively higher output,relatively better energy resolution and relatively shorter decay time.In addition,because of its structure characteristics,the crystal is suitable for growing up into large size,so it is easy for Cs₂NaGdBr₆:Ce crystal to be used in practical applications.Therefore,this paper considered Cs₂NaGdBr₆:Ce crystal as a kind of new and very potential scintillation crystal for industrialization,And then carried out the Cs₂NaGdBr₆:Ce crystal research work.The research content mainly includes two aspects: on the one hand,study on the Cs₂NaGdBr₆:Ce crystal growth technique have been made;On the other hand,a preliminary study on the crystal optical and scintillation performance have been made.Main research results of this study are as follows:?1?Using Bridgman method and spontaneous nucleation,We successfully acquired diameter-size 1.0 inch and 1.5 inch Cs₂NaGdBr₆:Ce blank crystal,Then after processing and packaging,We gained a finished Cs₂NaGdBr₆:Ce single crystal product with size ?25×25 mm3.?2?Through the long-term experiment grope,the suitable growth technological parameters were found:?1?For single crucible growth furnace,the optimum technological parameter of Cs₂NaGdBr₆:Ce crystal growth are as follows: the bottom of quartz crucible should be set at the top edge of temperature gradient,the temperature of high temperature zone should be set to 760?,and the crucible descent rate should be set to 0.4mm/h.?2?For multiple region growth furnace,the optimum technological parameter of Cs₂NaGdBr₆:Ce crystal growth are as follows: the bottom of quartz crucible should be set at the location above the base level 68 cm,the temperature of high temperature zone should be set to 740?,and the crucible descent rate should be set to 0.5mm/h.?3?By comparing the UV fluorescence spectrum and X-ray excitation emission spectrum after tests,We found that the spectrums have two similar emission peaks,which located around 383 nm and 418 nm,respectively corresponding to the Ce³⁺ 5d?4f^{1 2}F_5/2 and 5d?4f^{1 2}F_7/2 transition.In addition,a emission peak of weaker intensity appeared in the X-ray emission spectrum which located around 309 nm,corresponding to the characteristic Gd³⁺ 4f^{7 6}P_7/2?4f^{7 8}S_7/2 transition.?4?The light output,energy resolution and decay time of Cs₂NaGdBr₆:Ce single crystal excited by gamma rays was 40,000 ph/MeV,6.2% and 76 ns,respectively,indicated that the crystal is newly potential scintillation crystal.